Estimate your body fat percentage with the US Navy method
💡 Why This Matters Body fat percentage is a more accurate health indicator than weight alone. The US Navy method uses simple measurements to estimate your body composition, helping you understand if you're in a healthy range or may need lifestyle adjustments.
Measure just below the larynx
Measure at belly button level
Essential fat — the minimum needed for basic bodily function — is naturally higher in women (about 10-13%) than men (about 2-5%), largely due to fat's role in hormone regulation and reproduction.
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What is Body Fat Percentage? Body fat percentage measures the proportion of your body weight that is fat tissue versus lean mass (muscles, bones, organs, and water). Unlike BMI, which only considers weight and height, body fat percentage directly measures your actual composition. Understanding this number gives you a much clearer picture of your health than weight alone.
The US Navy Method Explained: This calculator uses the US Navy method, a widely accepted formula that uses neck, waist, and (for women) hip measurements to estimate body fat. The method works because waist circumference correlates with abdominal fat, which is the most metabolically active and health-relevant type of fat. The neck measurement helps account for upper body muscle mass.
Categories Explained: Essential fat is the minimum amount needed for basic bodily functions—around 2-5% for men and 10-13% for women. Athletes typically have 6-13% (men) or 14-20% (women). Fitness ranges are 14-17% (men) and 21-24% (women). Average is 18-24% (men) and 25-31% (women). Above these ranges indicates higher health risks.
Limitations to Consider: The US Navy method has limitations. It tends to underestimate body fat in very lean individuals and may overestimate in very obese people. It also doesn't account for muscle thickness variations. For a more accurate assessment, consider caliper testing or DEXA scans, which are considered the gold standard.
Using Your Results: Use your body fat percentage to set realistic goals. If you're in the athletic or fitness range, focus on maintaining healthy habits. If you're above average, small changes in diet and exercise can create meaningful improvements. Remember that health is multifaceted—body composition is just one piece of the puzzle.
Metric (male): Say you're male, 175 cm tall, with a 38 cm neck and 85 cm waist. Plug into the formula: 495 ÷ (1.0324 − 0.19077 × log₁₀(85−38) + 0.15456 × log₁₀(175)) − 450 ≈ 14.8%, landing in the Fitness range.
Imperial (female): Say you're female, 5'5" (65 in) tall, with a 13 in neck, 30 in waist, and 38 in hip. The calculator converts everything to centimeters first — 65 in → 165.1 cm, 13 in → 33 cm, 30 in → 76.2 cm, 38 in → 96.5 cm — then runs the female formula: 495 ÷ (1.29579 − 0.35004 × log₁₀(76.2+96.5−33) + 0.22100 × log₁₀(165.1)) − 450 ≈ 24.9%, landing in the Fitness range.
Fat distribution patterns differ by sex — the formula for women was calibrated using hip circumference as an additional predictor because it improves accuracy for typical female fat distribution, while the male formula relies on waist and neck alone.
It's a reasonable estimate for most people but less precise than gold-standard methods like DEXA scans or hydrostatic weighing. It tends to underestimate body fat in very lean individuals and can overestimate in people with higher body fat.
Yes — toggle between Metric (cm/kg) and Imperial (in/lb) at the top of the calculator. All measurements convert internally to centimeters before the formula runs.